So he made one excuse after another, but the Wolf, who was getting more and more suspicious every moment, would not listen to him.
So, as he had not courage to tell the truth, he was forced at last to swear an oath also, and this was what he swore:
"If it be that I stole the butter; if it be, if it be—
Then let some most deadly punishment fall on me, fall on me—
Whirrum wheeckam, whirrum wheeckam,
Whirram whee, whirram whee!"
After he had heard him swear this terrible oath, the Wolf thought that his suspicions must be groundless, and he would have let the matter rest; but the Fox, having an uneasy conscience, could not do so. So he suggested that as it was clear that one of them must have eaten the Keg of Butter, they should both stand near the fire; so that when they became hot, the butter would ooze out of the skin of whichever of them was guilty. And he took care that the Wolf should stand in the hottest place.
But the fire was big and the cave was small; and while the poor lean Wolf showed no sign of discomfort, he himself, being nice and fat and comfortable, soon began to get unpleasantly warm.
As this did not suit him at all, he next proposed that they should go for a walk, "for," said he, "it is now quite plain that neither of us can have taken the butter. It must have been some stranger who hath found out our secret."
But the Wolf had seen the Fox beginning to grow greasy, and he knew now what had happened, and he determined to have his revenge. So he waited until they came to a smithy which stood at the side of the road, where a horse was waiting just outside the door to be shod.
Then, keeping at a safe distance, he said to his companion, "There is writing on that smithy door, which I cannot read, as my eyes are failing; do thou try to read it, for perchance it may be something 'twere good for us to know."
And the silly Fox, who was very vain, and did not like to confess that his eyes were no better than those of his friend, went close up to the door to try and read the writing. And he chanced to touch the horse's fetlock, and, it being a restive beast, lifted its foot and struck out at once, and killed the Fox as dead as a door-nail.
And so, you see, the old saying in the Good Book came true after all: "Be sure your sin will find you out."